Barometers Illegal in Garbage & Drains Contains Mercury Hazardous Waste Never Throw Away Most antique barometers contain about 4 ounces of mercury. If your barometer contains mercury, it can be toxic to landfills, so dispose of it with hazardous waste. Ways to Reuse Repair Antique Barometers If you have a broken antique barometer, have it repaired instead of throwing it away. Check out The Barometer Shop, a store specifically dedicated to repairing antique barometers.